Agates can be found all around the world, in any location with past or present volcanic activity. Coastal locations or lakes are good places to find agates. In the United States, agates are mostly found in Oregon, Washington, Idaho and Montana. Other southwestern and western states can be go...
The formation of agates can take millions of years. The first step is for a crack or void to form in a rock. This can happen when the rock is heated or cooled unevenly, or when it is subjected to stress. Once a crack or void has formed, silica-rich groundwater can seep in. The ...
Some light-colored agates will turn brown or orange with heating, or black if they are first soaked in a sugar solution. These are sometimes sold as "carnelian," "onyx," or "black chalcedony." These heat treatments are permanent, but buyers should be informed because the "commercial identity...
Many agates can be found in volcanic rocks but are also common in metamorphic rocks. An agate is formedwhen water, rich in quartz molecules and other minerals, fills into small hollow spaces in rocks. The quartz molecules later form microcrystals that attach to the sides of the hol- low spa...
When a sand dollar dies and decays, its skeleton often washes up onto the ocean shore, especially if there's been a storm the night before. To find a sand dollar's skeleton, walk along the beach at low tide, paying close attention to the area just below the high-tide line. Look for...